app button not working / tray not opening?

I just got this phone a week ago and everything was working well on it. This morning I went to open the app tray and I hit the button to do so and nothing happened. The phone vibrated as if I pressed the button, it turned red, but nothing else. I tried to simply reboot the phone but still have the same issue...everything else works just fine with the phone...any ideas??

Usually when screwy things happen, like a computer, you turn the phone off a few and then turn it back on. If that does not fix, then a battery pull is next. Exactly what did you do to "reboot"? Cause to me that is a whole different thing than the things I just satated.